1. Field of the Invention
The present invention relates to communication networks, and more specifically to a method and apparatus for providing differentiated services on asynchronous transfer mode (ATM) switched virtual circuits (SVC) when transporting Internet Protocol (IP) packets.
2. Related Art
Internet Protocol (IP) packets are often transported on asynchronous transfer mode (ATM) based communication networks. It is often desirable to transport IP packets using switched virtual circuits (SVCs) at least in that the SVC can be set up and released as and when required, thereby potentially not tying up unused bandwidth and other resources (e.g., buffer space on ATM switches) on the ATM network.
One desirable feature in such ATM networks is that IP packets be provided differentiated services. Differentiated services typically facilitate attempts to transport IP packets consistent with different service requirements for each packet. Thus, at least some of the users (of IP packets) may be provided guaranteed superior services.
A situation where differentiated services using SVCs would be of particular interest is when IP packets specify a desired type of service (TOS) in a corresponding header field. The TOS field is described in further detail in RFC 791 entitled, “Internet Protocol”, which is incorporated in its entirety herewith. TOS is specified along the parameters precedence, delay, throughput, and reliability. It would be desirable to transport IP packets on SVCs providing the closest matching services (QOS) when the TOS field is specified for the IP packet. As IP packets may specify different TOS values, it would be desirable to provide differentiated services for IP packets when transporting on SVCs.
What is therefore needed is a method and apparatus which enables differentiated services to be provided to IP packets transported on ATM SVCs.